Ground reaction forces of Olympic and World Championship race walkers

Race walking is an Olympic event where no visible loss of contact should occur and the knee must be straightened until midstance. The purpose of this study was to analyse ground reaction forces of world-class race walkers and associate them with key spatiotemporal variables. Nineteen athletes race walked along an indoor track and made contact with two force plates (1000 Hz) while being filmed using high-speed videography (100 Hz). Race walking speed was correlated with flight time (r = .46, p = .049) and flight distance (r = .69, p = .001). The knee's movement from hyperextension to flexion during late stance meant the vertical push-off force that followed midstance was smaller than the earlier loading peak (p < .001), resulting in a flattened profile. Athletes with narrower stride widths experienced reduced peak braking forces (r = .49, p = .046), peak propulsive forces (r = .54, p = .027), peak medial forces (r = .63, p = .007) and peak vertical push-off forces (r = .60, p = .011). Lower fluctuations in speed during stance were associated with higher stride frequencies (r = .69, p = .001), and highlighted the importance of avoiding too much braking in early stance. The flattened trajectory and consequential decrease in vertical propulsion might help the race walker avoid visible loss of contact (although non-visible flight times were useful in increasing stride length), while a narrow stride width was important in reducing peak forces in all three directions and could improve movement efficiency.     

Effects of load mass carried in a backpack upon respiratory muscle fatigue

Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h^?1 wearing a backpack of either 0 (LC₀), 10 (LC₁₀), 15 (LC₁₅) or 20?kg (LC₂₀). Inspiratory (P_Imax) and expiratory (P_Emax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean P_Imax and P_Emax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.     

Factors affecting the career progress of academic accountants in Australia: Cross-institutional and gender perspectives

Since the late 1980s, Australian highereducation has undergone significant reforms andpolicy changes based on economic rationalismand modernisation of management. This paperexamines the outcomes of the reform processesbased on the career attributes, status andperceptions of work environment of academicaccountants in Australian universities.Similarities and differences between academicaccountants are explored fromcross-institutional and gender perspectives.The data provide insight into a number ofsystemic inequalities between the older andmore established universities and the neweruniversities. In specific, across-institutional analysis based on fouruniversity types: Sandstones/Redbricks,Gumtrees, Unitechs and New (Marginson 1999)indicates that academic accountants in Newuniversities employ a much lower proportion ofstaff with PhD qualification, a weakerpublication profile, and perceive greaterbarriers for conducting research in terms of ashortage of research mentors, colleagues withresearch experience, and post-graduatestudents. Further, the commitment to flexiblelearning and delivery strategies iscomparatively stronger in Unitechs, and posesadditional demands on accounting academics'overall workload. Perceptions of gender-baseddiscrimination by female academic accountantsare generally stronger than their malecounterparts, particularly, in Newuniversities. These results raise severalissues for academic accountants at both theinstitutional and individual level in terms ofequal employment opportunities, management ofresearch programmes, development of teachingstrategies and individual time management.     

声乐表演的二度创造--谈歌曲演唱的创作方法

从声乐表演的基本属性出发 ,阐明了歌曲声乐表演“从外到内”、再“从内到外”的分析、体验、表现作品的创作方法     

计算机处理器性能的衡量

处理器在整个计算机中占了很重要的部分,很多用户都关心处理器的性能表现如何以及怎样衡量它的性能.作者主要从两个方面介绍其性能的技术参数指标.     

校阅在CAT与FIT中对受测者行为表现与状态焦虑水平的影响

校阅(review)对CAT中受测者心理影响的研究有利于CAT的推广应用。J.Oleat等研究者在CAT(computerizedadaptivetest,计算机自适应性测验)与FIT(fixed-itemtest,固定项目测验)中,将校阅(review)对受测者行为表现与状态焦虑水平的影响作了比较研究。实验结果表明,在允许校阅的环境中,受测者正确反应与被估计的能力水平显著增加,并且状态焦虑水平下降。本文对J.Oleat等研究者的主要研究成果进行了详细的评述,并进一步探讨了在CAT中增设校阅(review)环境的重要性和可能性。     

议政府采购绩效审计

如何开展政府采购绩效审计,是审计机关及其审计人员亟须研究解决的一个课题。实施政府采购绩效审计,就必须从审计角度出发,就政府采购绩效审计的必要性、审计目标、审计的依据和内容进行思考。     

谈谈声乐表演专业学生的嗓音保护

透视当前嗓音保护的现象,阐述了嗓音保护的重要性,并结合教学实践,提出了一些保护嗓音的可行性方法.     

法律保护、控股股东与公司绩效分析

我国上市公司具有典型的股权集中特征,研究控股股东行为对于改善我国公司治理具有重要意义。控制权收益是控股股东最大化自身利益的载体。现实决策中,控股股东往往需要权衡公共收益和私人收益哪一个更有利于实现自身利益最大化。文章从法律保护角度出发,以控制权收益为切入点,构建了一个研究控股股东行为的分析框架。结合我国控股股东的实际情况,将该框架进一步具体化,用来解释我国国有控股公司与民营控股公司的绩效差异之谜。